I Read that I must play the notes from first guitar string(e bottom)and after that notes on the B G D A and hight E string,but sometimes guitar players hit two or three strings together and at the sametime for example look at this tab:

  E|-------0-----|-------0-----|-------0-----|-------0---7-| 
  B|-----0---0---|-----0---0---|-----0---0---|-----0---0---| 
6 G|---0-------0-|---0-------0-|---0-------0-|---0---------| 
8 D|-------------|-------------|-------------|-------------| 
  A|-------------|-------------|-------------|-------------| 
  E|-0-----------|-0-----------|-0-----------|-0-----------|

My question is that how I know what are the strings(notes) to play at the same time (fingerstylse to hit the strings top and bottom strings together?)for every song?